Wire drawing apparatus



R. M. GUTHRIE WIRE DRAWING APPARATUS Sept. 24, 1968 3 Sheets-Sheet 1 Filed Jan. 17. 1966 R. M. GUTHRIE WIRE DRAWING APPARATUS Sept. 24, 1968 5 Sheets-Sheet 2 Filed Jan. 1.7, 1966 61 8Q 6 A 84a p 1968 R. M. GUTHRIE 3,402,588

WIRE DRAWING APPARATUS Filed Jan. l7, 1966 3 Sheets-Sheet 3 /Z/ #9 I Z 7 United States Patent 3,402,588 WIRE DRAWING APPARATUS Robert M. Guthrie, Rockford, Ill., assignor to Fastener Engineers, Inc., a corporation of Illinois Filed Jan. 17, 1966, Ser. No. 521,115 15 Claims. (Cl. 72-289) ABSTRACT OF THE DISCLOSURE A wire drawing apparatus in which an intermediate section of a continuous length of wire is coiled around a rotary drum for pulling the wire through a wire drawing die, and clamp mechanism is provided on the drum for clamping the wrap of wire at the outlet end of the coil to the surface of the drum. The clamps are sequentially disengaged from the wire as the clamps rotate through a preselected sector of each revolution to allow unwrapping of the wire at the outlet end of the coil from the drum as the drum rotates.

This invention relates to apparatus for drawing wire and particularly to improvements in the wire feed means for pulling the wire through the drawing die.

Wire drawing apparatus have herefore been made which employed a drive drum for pulling wire through a drawing die, and wherein the drum had a wide drive surface to receive an intermediate coil of the wire composed of a number of wraps of wire having an inlet end where the wire from the die wraps on the drum and an outlet end where the wire from the die unwraps from the drum. The drums had a flange on the inlet end of the drum and, as the wire wrapped on the drum between the flange and the previous wrap of wire, it forced the previous wraps of wire axially along the drum toward the outlet end. In such apparatus the wire at the outlet end unwraps from the drum at the same rate as it wraps on the drum at the inlet end of the coil so that the number of wraps on the drum remains constant while the drum is in running. The wire that unwraps from the drum then passes to another apparatus, for example, a further wire drawing apparatus; a wire straightening machine; a machine which cuts or otherwise utilizes the wire; or to a wire winding apparatus.

In order to pull a wire through the drawing die, a force must be exerted on the wire which is approximately equal to the area reduction of the wire times the tensile strength of the wire. This force often exceeds three thousand pounds. It follows that the wire will be pulled through the die by the drum only when the coil is maintained sufficiently tightly around the drum to grip the drum and provide the traction necessary to overcome the draw box pull. When the tension at the outlet end of the coil is released, the coil can expand or loosen and the drum then slips relative to the coil.

It has heretofore been the practice to maintain suificient tension on the wire as it leaves the drum to prevent loosening of the coil on the drum. However, the tension which must be applied to the wire at the outlet end of the coil to stop slipping between the coil and drum increases markedly with increases in wire size and wire hardness or tensile strength. This is due in part to the increase in draw box pull with increased wire size and tensile strength, so that the tractive force between the drum and the coil of wire must be correspondingly increased. In addition, the larger the diameter of the wire, the greater is the tendency of the wire to uncoil from the drum, and similarly, the higher the tensile strength of the wire material, the greater is the tendency to uncoil. In drawing large diameter wire or wire of high tensile strength, the tension which had to be maintained on the wire leaving the drum to prevent loosening of the coil, often exceeded the capacity of the feed mechanism of the succeeding machine.

An important object of this invention is to provide a drum-type wire drawing apparatus which is capable of handling wire that is very stilt, either by reason of large diameter, material hardness or both, and which does not mar or damage the drawn wire.

Another object of this invention is to provide a drumtype wire drawing apparatus which does not require a constant or a substantial tension on the wire leaving the wire drawing drum in order to maintain driving engagement between the drum and the intermediate coil of wire disposed thereon.

Another object of this invention is to provide a wire drawing apparatus of the type wherein an intermediate coil of wire is disposed around the drive surface of the drum, the coil wrapping on the drum at one end and unwinding from the drum at the other end as the drum rotates, and which wire drawing apparatus has an improved arrangement for maintaining the outlet wrap of wire in tight engagement with the drum substantially independent of the tension on the wire leaving the drum.

Another object of this invention is to provide a wire drawing apparatus which substantially prevents rotational slipping between the drum and the intermediate coil of wire disposed thereon so as to minimize wear on the drum drive surface.

A more particular object of this invention is to provide a wire drawing apparatus of the type wherein an intermediate coil of wire is disposed around the drawing drum to wrap on one end of the drawing drum as it passes from the drawing die and to unwrap from the other end of the drum, and which apparatus has clamping means for clamping a wrap of wire adjacent the outlet end of the coil to the drum periphery to inhibit slippage therebetween.

Another object of this invention is to provide a wire drawing apparatus having clamps for clamping the wire to the surface of the drive drum, and an improved arrangement for actuating the clamps in timed relation with the rotation of the drum to open the clamps during one sector of revolution of the drum.

These, together with other objects and advantages of this invention, will be more readily appreciated as the invention becomes better understood, by reference to the following detailed description when taken in connection with the accompanying drawings wherein:

FIGURE 1 is a side elevational view of a wire drawing apparatus embodying the present invention;

FIG. 2 is a partial plan view of the wire drawing apparatus;

FIG. 3 is a fragmentary vertical sectional view through the wire drawing drum, with parts shown in elevation;

FIG. 4 is a fragmentary elevational view of the wire drawing apparatus showing the clamp means;

FIG. 5 is a sectional view of one of the clamp arms taken on the plane 55 of FIG. 4; and

FIG. 6 is a schematic diagram illustrating the fluid operated clamp mechanism and controls therefor.

The wire drawing apparatus in general includes a support base 10, a wire drawing drum 11 mounted for rotation on the base; a drum drive apparatus 12 operatively connected to the drum to drive the same, and a wire drawing die 13. The wire, after passing through the die 13, is wrapped a number of times around the drum 11 to form an intermediate coil and the other end of the coil unwraps from the drum as the latter rotates and passes to a succeeding apparatus such as an apparatus which cuts or otherwise utilizes the wire in forming parts; a wire straightening machine; a wire rewinding apparatus; or a further wire drawing apparatus. As used herein, the term intermediate coil refers to the coil on the drum which is formed intermediate the ends of the wire and wherein the wire continuously winds on to one end of the coil while unwinding from the other end of the coil so that a number of loops or wraps in the coil remains constant while the drum is in operation, but wherein the wire which forms one coil is continuously changing. The wire drawing apparatus of the present invention is particularly adapted for handling wire which, because of large diameter and/or material hardness or tensile strength, tends to slip on a conventional wire drawing drum. Thus, the wire drawing apparatus is adapted for use with a wide range of wire sizes including large diameter wires having a diameter of the order of inch or more. In order to inhibit slipping of the wire relative to the drum, apparatus is provided for clamping a wrap of the wire adjacent the outlet end of the coil to the drive surface of the drum. This inhibits loosening of the outlet end of the coil and accordingly maintains the other wraps of the coil in tight engagement with the drum. In clamping a wrap of wire to the drum adjacent the outlet end of the coil, the clamping action exerted by the clamps on the wrap of wire can be very small as compared to the total pull which must be exerted on the wire in order to draw it through the die. Stated otherwise, each of the wraps of wire on the drum exerts a gripping action on the drum so that the tension on the wire in each coil decreases in a direction from the inlet toward the outlet end of the coil. Therefore, only a relatively small clamping action is required to hold the last wrap of wire at the outlet end of the coil against slipping on the drum. The remaining wraps, that is those wraps which lie between the clamped wrap and the inlet end of the coil, provide the primary traction between the drum and the wire, so long as the wrap at the outlet end of the drum is clamped to the drum sufficient to prevent slipping of the last wrap. A means designated generally by the numeral is provided for actuating the clamps in timed relation with the rotation of the drum to disengage the clamps from the wire as the clamps rotate through a pre-selected sector of each revolution of the drum, to allow unwrapping of the wire at the outlet end of the coil. The actuating means for the clamps is so arranged that at least some of the clamps remain in clamping engagement with the last wrap of wire at all times to prevent slipping of the last wrap.

The drum is preferably mounted for rotation in a vertical plane, it being understood that it could be otherwise mounted for rotation for example in a horizontal plane, if desired. In the embodiment shown, the drum has a hub 21 which is non-rotatably connected as by key 22 to a shaft 23. The shaft 23 is rotatably supported on the base by stanchions 24 and 25 and by hearing blocks 26, 27. The drive motor 12 is drivingly connected to the drum through a speed reducing drive mechanism, herein shown in the form of a small diameter pulley 28 on the motor shaft and a large diameter pulley 29 on the drum shaft and a belt or belts 32 which interconnects the pulleys.

The wire drawing die 13 is mounted on a support pedestal 33 offset to one side of the periphery of the drum. The die and mounting are of conventional construction and, as shown, include a die block 34 having a die opening 35 through which the wire is drawn, and which opening is tapered in a direction from the inlet to the outlet end of the die. The die is conveniently supported in a lubricant box 36 having a compartment 37 for receiving lubricant and the like, and the box is preferably supported for swinging movement about a pin 38 and in a plane generally parallel to a tangent to the drum periphery to allow the axis of the die to align itself with the wire passing through the die when the wire is winding on the drum.

The drum has an annular drive surface 41 at its periphery, which drive surface is dimensioned so as to receive a plurality of wraps of wire in a single layer on the drive surface. It has been found that there should be at least six wraps of wire around the drive surface and preferably a greater number of the order of eight, nine or ten wraps of wire, in order to assure adequate traction without requiring excessively high clamping forces to be applied to the end wrap of wire. Accordingly, the drum is selected so as to have an axial width sufficient to receive at least six and preferably a larger number of the order of eight, nine or ten wraps of the largest size wire which is to be drawn through the machine. A flange 42 is provided at the inlet end of the drum to engage the wire as it wraps on the drum from the die and to cam or force that wire, and drive the preceding wraps which make up the coil, axially along the drive surface in a direction towards the other or outlet end of the drum. The flange has an inclined inner face 420 which engages the wire and which produces the aforedescribed camming action against the coil. In order to adapt the drum for handling widely different sizes of wire, it is preferable to form the drive surface in two sections, one of which is detachable from the drum, and which can be replaced with a section of different axial length to change the overall length to the drive surface. As shown, the flange 42 and a portion 41a of the drive surface are formed in a ring designated 44 which is separate from the drum, and which is detachably secured thereto as by fasteners (not shown). As will be seen, the ring member 44 can be removed and replaced with a ring member having a different axial length, to thereby increase or decrease the overall length of the drive surface as desired.

The wire designated w, after passing through the die 34, winds on the drum at the inlet end thereof adjacent the flange 42. The resistance of the wire drawing die maintains a high tension on the wire between the die and the drum and, as the initial wrap of wire indicated at w-l winds on the drum, it forces the previous wraps of wire axially along the drum toward the outlet end thereof. The wrap of wire indicated at w-2 at the outlet end of the drum unwraps from the drum and passes to a subsequent apparatus which may either be a machine that consumes the wire in making parts or a machine that rewinds the drawn wire for subsequent use. The wire as it unwinds from the drum preferably passes over one or more idler rolls which guide the wire and also serve a control function described hereinafter. As shown, the wire as it unwraps from the outlet end of the drum indicated at w-3 passes over one or more idler rolls 47 offset from the periphery of the drum, and the wire indicated at w4 then passes over the top of the drum to the next apparatus which operates on the wire. The idler roll 47 is shiftably supported on an arm 48, and in the embodiment illustrated, the arm is conveniently pivotally supported by a pin 49 on the pedestal 33. The arm is yieldably urged in a direction to take up slack in the wire w-3 after it leaves the drum and by an idler roll biasing mechanism 51. In the embodiment shown, the idler roll biasing mechanism includes a pneumatic cylinder 52 supported as by a pin 53 on the pedestal 33 and having a piston 54 connected through a rod 55 to the support arm 48. A pneumatic cushion is maintained in the cylinder 52 in a manner described hereafter to yieldably urge the piston and consequently the idler roll in a direction to take up the slack in the wire as it unwinds from the drum.

An important feature of the present invention resides in the provision of a clamp means for clamping the wrap of wire adjacent the outlet end of the coil to the drive surface of the drum to inhibit slipping of the clamped coil and to thereby maintain the remaining wraps of wire in tight engagement with the drum. This clamp means comprises a plurality of clamps 14 mounted on the drum for rotation therewith at points spaced circumferentially around the periphery of the drive surface. The clamps 14 each include a clamp member 61 supported for movement relative to the drum between a clamped position, in which they engage the outer periphery of the wrap of wire to clamp the same to the drive surface, and a release position in which they are laterally offset from the wrap of wire to allow unwrapping of the same. The clamp members 61 are preferably mounted for swinging movement between their clamp and release positions and, as shown, are supported by a pin 62. on a bracket 63 attached to a clamp mounting ring 64 on the drum. The pivot pin 62 for the clamp members is laterally offset from the drive surface, and supports the arms for swinging movement between the clamped position shown at the top of the drum in FIG. 3, in which the arms extend inwardly in overlying relation to the drive surface and engage the outer periphery of a wrap of wire at the outlet end of the coil, and a release position shown at the bottom of FIG. 3 in which the arms extend outwardly from the periphery of the drum and are laterally offset from the clamped coil to allow unwrapping of the same. Individual power actuators 15 are preferably provided for each of the clamp means 14, and these actuators are advantageously of the fluid operated type. As shown, the actuators include a cylinder 67 which is pivotally supported at one end by a pin 68 on a bracket 69 secured to the clamp mounting ring 64. A piston is disposed in the cylinder and has a rod 71. A toggle joint is preferably provided for operatively connecting the power actuator 15 with the clamp for moving the clamp member between its clamped and release positions and for increasing the force supplied by the actuator to the clamp member when the latter is in its clamped position. This toggle joint includes a bell crank 75 pivotally mounted at 76 on the bracket 63 and having a pivotal connection at 77 to the actuator rod 71. The bell crank is connected through a link 78 to the clamp arm, the link being pivotally connected by a pin 79 to the bell crank and by a pin 81 to the clamp member at a point eccentric to the pivot axis 62 of the clamp member. As will be seen from FIG. 4, the portion of the bell crank between the pivot pins 76 and 79 forms one link and as this link approaches alignment with the link 78, the force applied by the toggle joint also increases to a very high value. This provides a firm clamping action even with relatively low pressure fluid actuators.

It has been found preferable to clamp only the last wrap of wire in the coil and a wire engaging face member 84 is mounted on each clamp member and is so con structed and arranged as to assure proper clamping of only the end wrap of wire. In particular, the wire engaging face member 84 has a wire engaging face 85 at the underside thereof and, in order to assure engagement with only the end wrap of wire, the wire engaging face has an end portion 85a which is inclined slightly, of the order of four or five degrees with respect to the drive surface so as to converge in a direction toward the outlet end. This assures that the clamp member only engages the end wrap of wire at the outlet end of the coil, even though the clamp member may extend sufiiciently far to partially overlie the next adjacent coil. The wire engaging face member is also advantageously made adjustable relative to the clamp member to vary the spacing between the wire engaging face and the drive surface when the clamp member is in its clamped position, to thereby accommodate wire of different size. As shown, the clamp member has a general U-shaped configuration with a base portion 84a underlying the respective clamp member and spaced leg portions 84b overlying opposite sides of the clamp member. The face members are adjustably secured to the clamp members by fasteners 88 which extend through enlarged openings 86 in the leg portions 84b and through the clamp members. Shims 89 of different thickness are adapted to be inserted between the base portion 84a of the face members and the underside of the clamp members to vary the spacing between the face 85 and the drum drive surface and, advantageously, the opposed faces 84c and 610 on the face members and clamp members respectively are inclined in a direction lengthwise of the clamp members so as to produce a wedging action when the face members are moved lengthwise of the clamp members to thereby provide fine adjustment of the spacing between the face members and the drive surface of the drum.

A valve means is provided for sequentially operating the actuators 15 to open or release the clamp members as they move through one sector of each revolution and to move the clamp members to their clamping position as they move through a different sector. The valve means preferably include a plurality of valves 91 each individual to a respective actuator 15. The valve members 91 are mounted for rotation with the drum as by brackets 92 and are conveniently positioned on the drum at positions corresponding the circumferential locations of the clamp members. The actuators 15 are advantageously the double acting type and the vlave means 91 is of the 4-way type which is arranged in one position thereof to apply fluid pressure to one end of the cylinder and exhaust the other end to atmosphere, and to reverse the fluid pressure on the cylinder in the other position of the valve member. As diagrammatically shown in FIG. 6, the valve members each include an inlet port 91a, first and second control ports 91b and 910, and exhaust ports 91e. A valve member 93 having elements 93a and 93b is operative in one position thereof to communicate the inlet port 91a with the outlet port 91c while communicating the outlet port 91b to the exhaust port 91a and, in the other position thereof to communicate the inlet port 91a with the outlet port 91b and to communicate the outlet port 910 with the exhaust port 916. Fluid such as air under pressure is supplied to the inlet ports of the several valves by way of a conduit 101 and a rotary coupling 102. The coupling 102 is conveniently connected to the shaft 23 and is arranged to transmit fluid pressure from the stationary line 101 to the rotating shaft. The shaft has a passage 104 therein which is connected to a distributor 105, herein shown in the form of lateral passages in the outer end of the shaft 23. The lateral passages are connected through lines 106 to the inlet port 91a of the respective valves. The control ports of the valves are connected through lines 107a and 10711 to opposite ends of the respective fluid actuator cylinder 67. A cam means is provided for actuating the valves in timed relation with the rotation of the drum. This cam means is conveniently in the form of a cam ring 111 which remains stationary as the drum rotates. As shown in FIGS. 3 and 6, the cam ring closely surrounds a portion 21a of the drum hub 21 so as to be radially centered thereby, but to also allow relative rota tion therebetween. The cam ring is held against rotation by mounting on stationary support brackets 112 and 113 attached to the base 10 and, preferably, the ring is supported for limited angular adjustment to adjust the timing of the valve actuation. As diagrammatically shown in FIG. 6, the ring 111 has arcuate slots 115 therein to which the ring mounting bolts 116 extend. The bolts can be loosened and the ring angularly adjusted to vary the angular position of the cam ring.

The cam ring is constructed and angularly adjusted so as to actuate the valves to release the clamps during that sector of each revolution in which the wire is unwrapping from the periphery of the drum. In the form shown, the wire begins to unwrap as the clamp approaches its lowermost position. As shown in FIG. 6, the cam ring 111 has a dwell portion 111a and a lobe portion lllb. The lobe portion is so arranged as to engage the followers 113 on the valve members to move each valve from its normal position to a position in which it releases the clamps. The lobe has an arcuate extent suflicient to hold the valves in a position opening the clamps as the clamps move through a preselected sector to allow the wire to unwrap from the drum and such that the clamps during subsequent reclosing, do not engage the wire w-3 as it unwraps from the drum. As the followers move off the dwell portion 11b, the valves move back to their first position and actuate the clamps to reclamp the wire to the drum.

The angular position at which the clamps are actuated to release the wire will obviously depend upon the point at which the wire normally unwraps from the drum, and this point will vary with different machines and may also vary for different wires. For example, the wire could be so arranged as to unwrap from the drum adjacent the top of the drum instead of at the bottom of the drum as shown, and under these conditions the cam would be so arranged as to operate the clamps to release the same as the clamps approach the top of the drum.

The number of clamps employed can also be varied. However, it is necessary to employ a minimum of two clamps so that one clamp will at all times be in clamping engagement with the wire. It is preferable to employ more than the minimum and, in the form shown, four clamps are employed, it being understood that a greater number may be employed if desired or necessary for adequate clamping. In order to achieve maximum clamping etfect with four clamps, the cam lobe 111b is preferably arranged so as to hold the clamps open through a sector of less than 90 so that at least three of the clamps are in clamping engagement with the wire at all times. In the event it is necessary to hold the clamps open for an angle of greater than 90, the use of additional clamps is desirable.

It is sometimes necessary to release all of the clamps at one time, as when initially Winding the wraps of wire around the drum in connection with starting of the Wire drawing apparatus. This is conveniently achieved by providing a fluid actuator 121 on each of the valves 91, and which actuators are operatively connected to the valve member to move the same. The fluid actuator may be of any conventional construction having a piston, diaphragm or the like for moving the valve member and a manually controlled valve 122 is provided for applying fluid pressure to all of the actuators 121 to operate all of these valves 91 to a position to release the clamps. In the form diagrammatically shown in FIG. 6, the actuator 121 is of the single acting type and has a spring 120 for yieldably urging the valve member to one position and a piston or diaphragm 119 operatively connected to the respective valve member 93 to move it in the other direction. The valve mamber 122 is of a three-way type and has an inlet 125 connected through a line 126 and fitting 127 to receive fluid pressure from the passage 104. The valve 122 has a controlled outlet 128 connected through lines 129, 130, 131, and 132 to each of the several actuators 91. The valve also has an exhaust outlet 133 and a valve member 134 which is manually movable between a normal position shown in FIG. 6 venting the actuators 91 to atmosphere, and a second position in which it applies pressure to the actuators from the inlet 125. The valve 122 is mounted for rotation with the drum and is conveniently located in a region such as inside the ring 64 wherein it is protectively enclosed to avoid accidental operation.

The fluid actuators for the clamps are herein of the type which are pneumatically operated and air is supplied from a line 141 through a filter 142, a pressure regulating valve 143 and lubricator 144 to the inlet 101. Air pressure is also supplied through a line 145, a second pressure regulator 146, check valve 147 and manually operable three-way release valve 148 to the pneumatic cylinder 51 for taking up slack in the wire as it unwinds from the drum. As will be seen, adjustment of the regulator 1146 controls the pressure and hence the tension maintained on the line and the check valve operates to prevent reverse flow through the line so as to maintain the pneumatic cushion in the cylinder 52. The valve 148 is provided to enable selective discharge of the pneumatic cushion in the cylinder to release the wire tensioning means.

The drum with the clamps for clamping the wrap of wire at the end of the coil to the drum effectively prevents slipping of the coil relative to the drum. It is accordingly necessary to control the Wire drawing apparatus in such a manner as to correlate the output of the wire drawing apparatus to the succeeding machine. This can be achieved in part by the conventional speed control apparatus (not shown) which enables selective control of the speed at which the drum is rotated by the motor 12. It is customary to adjust the speed at which the drum is driven so as to be slightly in excess of the rate at which the wire is consumed by the next succeeding machine and then to periodically stop the wire drawing apparatus to accommodate the difference. This is conveniently achieved by a switch 161 diagrammatically shown in FIG. 6 as being operated by idler roll support arm 48. The switch 161 operates through a suitable motor control circuit 162, to stop the motor 12 whenever the slack in the wire becomes excessive, and to automatically restart the motor when the slack has been taken up.

A stationary wire clamp 171 is preferably provided for clamping the wire to the drum when the drum is stopped, and to hold the wire on the drum during initial starting of the same. This clamp is herein shown mounted on a lever 172 secured to a shaft 173 and is moved into and out of its clamp position as by a cylinder 174 (FIG. 2). The application of fluid pressure to the cylinder 174 can be controlled in any suitable manner as by a valve mechanism 175 (FIG. 6) which may be either manually or automatically operated to move the stationary clamp member against the wire on the drum, when the drum is stopped.

From the foregoing it is thought that the construction and operation of the wire drawing apparatus will be readily understood. When initially winding the wire on the drum during start-up of the drawing apparatus, the end of the wire is initially anchored to the drum in any conventional manner, as by a chain, and the valve 122 is actuated to apply pressure to the valve actuators 91 to release all of the clamps 14 on the drum. After a preselected number of wraps have been wound on the drum, the previously anchored end of the wire is released from the drum and is entrained over the idler roll 47, and the valve 122 is then moved back to its normal position shown in FIG. 6 to allow the valves 91 to move to positions controlled by the cam 111. When making this change-over, the stationary wire clamp 171 is moved into clamping position to hold the wire on the drum. As the drum rotates, the lobe 1111) actuates the valves 91 to release the clamps in one sector of each revolution corresponding to the zone in which the wire unwraps from the drum. The valves 91 move back to a position to reclose the clamps during the remaining portion of each revolution, while the followers engage the dwell portion 111a of the cam. As previously described, the lobe is preferably so arranged that a plurality and preferably at least three of the clamps are in clamping position at all times. The pressure applied by the clamps to clamp the last wrap of wire to the drive surface can be regulated by adjusting the regulator valve 143. Preferably, only the end wrap of wire is clamped to the drive surface. When the end wrap is clamped to the drum, the other wraps between the clamped wrap and the inlet end of the coil tightly grip the drum and provide the major portion of the traction between the drum and coil.

While a preferred embodiment of the invention has been shown and described, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention as defined in the appended claims.

I claim:

1. In a wire drawing apparatus including a wire drawing die; a drum drive apparatus; and a drum drivingly connected to the drive apparatus for receiving an intermediate coil of wire composed of a plurality of wraps of wire and having an inlet end where the wire from the die begins to wrap on the drum and an outlet end where the wire unwraps from the drum, said drum having an annular drive surface, the axial width of which is sufficient to receive the plurality of wraps of wire of the coil in a single layer on the drive surface, said drum having a flange at the inlet edge of the drive surface for engaging the wire as it wraps on the drum at the inlet end of the coil to progressively slide the coil in an axial direction along the drive surface toward the outlet end of the drive surface, the improvement comprising: at least two clamp means rotatable with the drum for clamping the wire to the drive surface at points spaced circumferentially around the periphery of the drive surface and spaced axially from said flange a distance at least as great as the thickness of several wraps of wire, and means for sequentially disengaging said clamp means from the wire while each clamp means moves through a preselected sector of each revolution.

2. An apparatus according to claim 1 in which said clamp means each include a clamp member mounted on the drum for swinging movement in a plane generally radially of the drum, and means for moving said clamp members between a clamp position overlying the drive surface of the drum and a release position extending outwardly from the drum.

3. An apparatus according to claim 2 wherein said clamp member moving means includes a toggle joint, said clamp members having wire engaging faces adjustable relative to the clamp members to vary the clearance between the Wire engaging faces and the drive surface of the drum when the clamp members are in their clamp position to accommodate different wire sizes.

4. An apparatus according to claim 1 wherein said clamp means each include a fluid actuator, valve means mounted for rotation with the drum for controlling the supply of fluid to the fluid actuators, and means for operating said valve means in timed relation with the rotation of said drum.

5. The combination of claim 4 including selectively operable means for simultaneously moving all of said valve means to a position in which they operate the fluid actuators to release said clamp means.

6. In a wire drawing apparatus including a wire drawing die; a drum drive apparatus; and a drum drivmgly connected to the drive apparatus for receiving an intermediate coil of wire composed of a plurality of wraps of wire and having an inlet end where the wire from the die begins to wrap on the drum and an outlet end where the wire unwraps from the drum, said drum having an annular drive surface, the axial width of which is sufficlent to receive the plurality of wraps of wire of the coil in a single layer on the drive surface, said drum having a flange on the inlet end of the drive surface for engag ng the wire as it wraps on the drum to progressively slide the coil in an axial direction along the drive surface toward the outlet end of the drive surface, the improvement comprising: at least two clamp means mounted on the drum at circumferentially spaced points therearound adjacent the outlet end of the drive surface, said clamp means each including a clamp member movable between a clamp position overlying the outlet end of the drive surface and engaging the wrap of wire at the outlet end of the coil to clamp that wrap against the drive surface and a release position in which the clamp membendisengages the wrap of wire at the outlet end of the C011 to allow the outlet end of the coil to unwind, and clamp operating means for operating said clamp members to individually move the clamp members to said release position as they rotate with the drum through one sector of each revolution and to move the clamp members to said clamp position as they rotate with the drum during a different portion of each revolution.

7. An apparatus according to claim 6 wherein said operating means includes a power actuator individual to each clamp member for moving the same between said clamp and release positions, and means for controlling operation of the power actuators in timed relation with the rotation of the drum.

8. An apparatus according to claim 6 wherein said operating means includes a fluid pressure type actuator individual to each clamp member, and valve means controlling the supply of fluid pressure to said actuators in timed relation with the rotation of said drum.

9. An apparatus according to claim 6 wherein said operating means includes a fluid pressure type actuator individual to each clamp member, a valve means individual to each actuator for controlling the application of fluid pressure to the actuators, and cam means for operating said valve means in timed relation with the rotation of the drum.

10. An apparatus according to claim 6 including a common manually controlled means operatively connected to each of the valve means for simultaneously operating all of the valve means to move the clamp mem bers to their release position.

11. An apparatus according to claim 6 wherein said clamp members are supported for swinging movement in a plane generally radially of the drum, said operating means for the clamp members including power actuators individual to each clamp member, and a toggle joint connecting each power actuator to a respective clamp member for moving the clamp member between its clamp and release positions and for increasing the force applied by the actuator to the clamp member when the latter is in its clamp position.

12. An apparatus according to claim 11 wherein said clamp members each have a wire engaging face member mounted thereon for adjustment relative to the clamp member in a direction to vary the clearance between the drum drive surface and the wire engaging face when the clamp members are in their clamp position to accom modate different wire sizes.

13. An apparatus according to claim 12 wherein the wire engaging face member underlies the clamp member when the latter is in its clamp position, said wire engaging face member and said clamp member having opposed faces inclined in a direction lengthwise of the clamp member with respect to the outer face of the wire engaging face member, and means mounting the face member on the clamp member for adjustment lengthwise of the latter.

14. An apparatus according to claim 6 wherein said clamp members have a wire engaging face which is spaced radially from the drive surface when in said clamping position to engage the outer periphery of the wrap of wire at the outlet end of the coil, said wire engaging face being inclined to converge slightly with respect to the drive surface in a direction toward the outlet end of the drive surface when the clamp member is in its clamp position.

15. An apparatus according to claim 6 wherein the drum has at least four of said clamp means uniformly spaced around the periphery thereof, said clamp operating means being so arranged that at least three of said clamp means are in clamping position at all times.

References Cited UNITED STATES PATENTS 1,963,456 6/ 1934 Worthington 72 289 2,717,072 9/1955 Andrews et al .a 72-289 3,280,611 10/1966 Lathom et a1. 72-289 2,752,797 7/1956 Sherwin 74-230.24

FOREIGN PATENTS 834,654 5/1960 Great Britain.

CHARLES W. LANHAM, Primary Examiner. E. M. COMBS, Assistant Examiner. 

